Tell me you don't live in a cold climate without telling me you don't live in a cold climate.

In a cold winter, you put the heat source inside the house, not outside :p And if that's too warm, you just open the window. Even if those gpus took the full 1800 watts from the power outlet, that's still not enough to overcome a cold breeze from an open window when it's -30C or even just -20C outside.